Thermoplastic films, sheets and fibers made from polyester, nylon and the like are superior in heat resistance, dimensional stability, mechanical strength and the like, so that they have been conventionally used widely and in large scale as films and sheets for packaging and industrial purposes; fibers including filament and/or staple fiber; and sheets of knitted fabrics made of said fibers, non-woven fabric and the like. While polyethylene, polypropylene, polyvinyl chloride and the like are inferior in heat resistance, they are still generally used for packaging, due to their superior formality, economical aspect and the like. However, a synthetic resin is generally hydrophobic and easily causes static electricity on the surface of a structure that it constitutes. Consequently, it easily attaches dust and so on to the surface thereof, thereby creating various troubles.
In generality, a surfactant is used for preventing electrification of film, sheet, fiber and the like. However, surfactants cannot provide a surface resistance sufficient (not more than 10.sup.10 .OMEGA./.quadrature.) to prevent attachment of dirt, dust and the like, and the antistatic performance thereof is subject to variation according to ambient humidity and moisture. A surfactant lowers the surface resistance of a film and the like, but low humidity strikingly increases the resistance to the extent that the desired antistatic performance cannot be attained.
As a result, attaching of the dust to the surface of a film, sheet and the like follows, causing various troubles. In a technologically highly advanced society of today, film, sheet and the like are increasingly desired, which are free of problems caused by static electricity even under low humidity environment. To meet this requirement, an antistatic agent has been demanded which gives a surface resistance of not more than 10.sup.10 .OMEGA./.quadrature. even under low humidity. The material giving such low surface resistance is known to be a conductive polymer such as polyaniline, polypyrrole and the like. Inasmuch as these are soluble in certain organic solvents but insoluble or undispersible in water and a mixed solvent of water/alcohol, a conductive polymer having a sulfonic acid group bonded to an aromatic ring thereof is used. In addition, since they fail to provide sufficient film characteristics by a single use thereof, a water soluble or water dispersible resin is mixed with the conductive polymer. When a resin having fine compatibility with sulfonated polyaniline is used, however, the desired surface resistance cannot be achieved, whereas when the desired surface resistance has been achieved, the surface becomes cloudy, impairing transparency inherent to a film made from such polymer.